ii. For each source in the best order, do the following merge:
(Our base has sources:
- the branch for each direct dep
- - the remote base)
+ - the remote base
+ - the topgit base, if this is a topgit import)
Find the (latest) common ancestor.
For each unwanted dependency removal (ie for each such
branch), search as follows:
* An "unwanted removal commit" is a non-merge commit in the
- history of the source, which unwantedly removes the dep
- from the actual included deps.
+ history of the source, which removes the dep from the
+ actual included deps.
* But the search stops at any point where we would have to
traverse a commit where .topbloke/deps is empty (which
stops us looking into the hitory of non-topbloke-controlled
from the source.
iii.
+ Check whether our list of dependencies has changed. If so
+ we need to restart the whole base update.
+
+ iv.
Check for missing or unwanted dependency inclusions. Compare
our base's desired included deps with our base's actual
included deps. In exceptional conditions, they will not
* Attempt to apply the appropriate diff to add (resp. remove)
the contents of the relevant patch (adjusted appropriately
for metadata, XXX??? particularly the actual inclusion list)
+ XXX if we want to add a dep we need to update the dep first
* Go round again looking for another discrepancy.
3. Update our branch.
Our branch has sources:
- our base
- the remote for our branch
+ - the topgit branch, if this is a topgit import
For each source in the best order, do the merge.
Double-check the actual dependency inclusions. In
Operations like "go up the stack", goes towards leaf. Hopefully unique.
"Down" the stack, uses a "conventional" linearisation
Stack reordering op ? auto adjust deps
+
+
+When merging, we need to DTRT with our metadata.
+Do this by running write-tree/read-tree etc. ourselves ?
+For a source we're merging from, we make a version where the
+metadata we shouldn't be merging is removed ?
+Or something.
+Have discovered that specifying a custom merge driver for a file does
+not have any effect if the three-way-merge looks trivial based
+on looking at the file contents - at least, if you use git-merge.
+
+Only thing which knows how to do all the gitattributes stuff and
+conflict markers and what have you is git-merge. (git-merge-tree does
+too but the output format is unsuitable.) "git-merge-index
+... git-merge-one-file" does not honour the merge drivers and is,
+contrary to what the git docs seem to suggest but don't actually
+state, not actualy used by git-merge.
+
+OK so here is a plan:
+ Use git-merge --no-commit
+ Perhaps on a HEAD, and/or against a tree, which have been massaged
+ to make the metadata suitable as input.
+ Filtering out the "merge was successful but we aren't committing"
+ message. Use a single pipe for stdout/stderr to get interleaving
+ right; the message from git-merge is not i18n'd.
+ Afterwards we:
+ Check for merge success in the index and compare to exit status
+ from git-merge (which is 1 if the merge failed).
+ Adjust the metadata.
+ Print appropriate big fat warnings if we have merge conflicts in our
+ metadata.
+ Commit, adjusting the parents of the new commit to the original
+ parents if we made the merge with special massaged parents.
+ We may still need to have custom merge drivers for metadata.
+
+
+Strategies for each metadata file merge:
+
+ in base/tip same patch & branch dep -> base base -> tip
+
+ msg T textual merge rm from src not in src
+ deps B list merge rm from src rm from src
+ deleted T std existence merge rm from src not in src
+ patch- BT must be same rm from src must be same
+ topgit- B std exist/text merge rm from src rm from src
+ [^+]*- ?? textual merge rm from src rm from src
+ +included BT list merge rm from non-tb src list merge
+ +*- ?? textual merge rm from non-tb src textual merge
+ *[^-] ?? die, aborting all ops, if found in any tb src or branch
~ian / topbloke.git / blobdiff